In the recovery of oil from a subterranean oil-bearing formation, it is possible to recover only a portion of the oil in the formation using primary recovery methods that utilize the natural formation pressure to produce the oil. A portion of the oil that cannot be produced from the formation using primary recovery methods may be produced by improved or enhanced oil recovery (EOR) methods.
Typically, further oil is produced from the formation after primary recovery by injecting water into the formation to mobilize oil for production from the formation. The injected water may drive a portion of the oil in the formation to a well for production from the formation. When a significant quantity of fractures extend through the formation, the injected water may preferentially flow through the fractures while leaving portions of the formation having lower fluid permeability untouched by the waterflood. As a result, a significant quantity of oil located in the portions of the formation having lower fluid permeability than the fractures may be left in the formation and not recovered by the waterflood.
Improvements to methods of recovering oil from an oil-bearing formation having a significant number of fractures extending therein are desirable.